Show orders with credit as paid in customer account

[nicolasVr]

What? Why?

• Closes When a customer has a credit it is tagged as non paid in customer account #14197

When a customer overpays an order (e.g. a product is removed after payment), the order gets a payment_state of credit_owed. In the customer account's Past Orders table, such orders were displayed as not paid ("No" in the Paid? column), which is misleading — the customer has actually paid more than required.

The Order#paid? method already handles this correctly, returning true for both paid and credit_owed states. The bug was in the frontend: the Past Orders template was comparing payment_state directly against 'paid', missing the credit_owed case.

Fix: Add a paid boolean attribute to Api::OrderSerializer that delegates to Order#paid?, and use order.paid in the template instead of the raw payment_state comparison. This keeps the logic in one place (the model) and avoids the frontend duplicating payment state knowledge.

Before — order with credit shows "No":
See Order # R367266433 at state "Credit owed"

After — order with credit correctly shows "Yes":

What should we test?

1. Create an order for a customer and mark it as paid (payment total = order total).
2. Remove a product from the order or reduce a quantity, so the customer has paid more than the new total.
3. Go to the customer's account page (/account) → Past Orders.
4. Verify the order shows Yes in the "Paid?" column (previously showed "No").

Also check that a genuinely unpaid order (balance due) still shows No.

Release notes

Changelog Category (reviewers may add a label for the release notes):

• User facing changes
• API changes (V0, V1, DFC or Webhook)
• Technical changes only
• Feature toggled

[rioug]

Looks good ! Thanks for your help @nicolasVr 🙏